1. Field of the Invention
The present invention relates to a multiboiler or a multi-water heater (hereinafter “multiboiler”) for preventing exhaust gas backflow and a method of controlling the same, and more particularly, to a multiboiler that prevents exhaust gas backflow using a wind pressure sensor and a controller which are provided for each boiler without having a damper, and a method of controlling the multiboiler.
2. Description of the Related Art
In general, combustion apparatuses such as a boiler or a water heater are designed to correspond to each desired capacity. However, there is a method of arranging and using a plurality of low-capacity boilers or water heaters in a line to correspond to a desired capacity. For example, a boiler of 200,000 kilocalories per hour (kcal/h) is achieved by arranging five boilers in a line, each of which having a capacity of 40,000 kcal/h. The boilers or water heaters arranged as described above are called a multiboiler or a multi-water heater.
The multiboiler can be installed in a small space and its maintenance and management are convenient, and even if one boiler breaks down, it is possible to significantly reduce inconvenience of use by controlling other boilers that have not broken down. Further, the multiboiler is advantageous in terms of energy saving because it is possible to individually operate several boilers, depending on the desired capacity.
FIG. 1 is a schematic view of a multiboiler in the related art.
Boilers constituting a multiboiler are each provided with a wind pressure sensor 20 that measures the wind pressure of air flowing into a combustion chamber 10 and a controller 30 that controls the number of revolutions of a fan that supplies the air into the combustion chamber according to the measured wind pressure. In addition to this function, the controller 30 performs a function of controlling various parts for operating the boiler. The controllers 30 provided in the boilers are connected with each other by a communication line 50.
In this multiboiler, mainly, only some of the boilers are operated to correspond to desired heating capacities, and exhaust gas of the boilers that are in operation frequently backflows into the combustion chambers of other boilers that are not in operation. For example, when the leftmost boiler in the figure is in operation and the other boilers are not in operation, the exhaust gas discharged from the leftmost boiler may flow into the combustion chambers of the other boilers, as shown by the arrows.
When the non-operating boilers with the exhaust gas in the combustion chambers are operated, oxygen is not sufficiently supplied by the exhaust gas therein, which may cause a non-ignition or an explosive ignition. To prevent backflow of the exhaust gas, a damper 60 is generally disposed at the exhaust port 40 for each boiler, such that gas is discharged only in one direction and cannot flow inside the combustion chamber in the opposite direction.
FIGS. 2 and 3 are schematic views of examples of dampers disposed in the multiboiler in the related art. A damper 61 shown in FIG. 2 is fixed by a hinge, such that the exhaust port 40 is opened toward the exhaust pipe by the pressure of the exhaust gas discharged out of the combustion chamber 10, but does not open to the combustion chamber 10. Further, as for a damper 62 shown in FIG. 3, the exhaust port 40 is opened and the exhaust gas can be discharged toward the exhaust pipe while the damper 62 is lifted by the pressure of the exhaust gas discharged out of the chamber 10, and the exhaust port 40 is closed after discharging is finished.
However, as the dampers 61, 62 are mechanically operated, their performance deteriorates when they are used over a long period of time, and as a result, there is a problem in that they will not perform their function as dampers. Accordingly, critical damage may be caused by backflow of exhaust gas when the dampers are not operating normally.